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Bismuth Subhalides
Bismuth-containing solid-state compounds pose an interest to both the physical inorganic chemists as well as condensed matter physicists due to the element's massive spin-orbit coupling, stabilization of lower oxidation states, and the Inert-pair effect, inert pair effect. Additionally, the stabilization of the Bi in the +1 oxidation state gives rise to a plethora of subhalide compounds with interesting electronics and 3D structures. Overview of subhalide bismuth solid-state chemistry Topological insulators and the relationship to bismuth solid-state chemistry Bismuth subhalides, such as Bi4Br4 and β-Bi4I4, have been recently reported as topological insulators. Topological insulators have caught attention of physical inorganic chemists as well as condensed matter physicists due to the unique physicochemical properties emerging upon transition from bulk to surface states. Exhibiting an energy band gap of classic insulator, the edge/surface states of the material acquire dissipati ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inert-pair Effect
The inert-pair effect is the tendency of the two electrons in the outermost atomic ''s''-orbital to remain unshared in compounds of post-transition metals. The term ''inert-pair effect'' is often used in relation to the increasing stability of oxidation states that are two less than the group valency for the heavier elements of groups 13, 14, 15 and 16. The term "inert pair" was first proposed by Nevil Sidgwick in 1927. The name suggests that the outermost ''s'' electron pairs are more tightly bound to the nucleus in these atoms, and therefore more difficult to ionize or share. For example, the p-block elements of the 4th, 5th and 6th period come after d-block elements, but the electrons present in the intervening d- (and f-) orbitals do not effectively shield the s-electrons of the valence shell. As a result, the ''inert pair'' of ''n''s electrons remains more tightly held by the nucleus and hence participates less in bond formation. Description Consider as an example thalli ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topology (other)
Topology is a branch of mathematics concerned with geometric properties preserved under continuous deformation (stretching without tearing or gluing). Topology may also refer to: Mathematics *A topology is the collection of open sets used to define a topological space Electronics *Topology (electronics), a configuration of electronic components Computing *Network topology, configurations of computer networks ** Logical topology, the arrangement of devices on a computer network and how they communicate with one another Geospatial data * Geospatial topology, the study or science of places with applications in earth science, geography, human geography, and geomorphology **In geographic information systems and their data structures, topology and planar enforcement are the storing of a border line between two neighboring areas (and the border point between two connecting lines) only once. Thus, any rounding errors might move the border, but will not lead to gaps or overlaps betwe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bismuth Compounds
Bismuth forms mainly trivalent and a few pentavalent compounds. Many of its chemical properties are similar to those of arsenic and antimony, although much less toxic. Oxides and sulfides At elevated temperatures, vaporized bismuth metal and oxygen combine into the yellow trioxide, . Wiberg, p. 768. Greenwood, p. 553. At temperatures above 710 °C, this (molten) oxide corrodes all known oxides and even platinum. Krüger, p. 185 It forms two series of oxyanions in basic conditions: linear, chain-polymeric ; and cubic . In , the anion forms the octamer ; in , the tetramer. The dark red bismuth(V) oxide, , is unstable, liberating gas upon heating. The compound NaBiO3 is a strong oxidant. Greenwood, p. 578. Bismuth sulfide, , occurs naturally in bismuth ores, but can be synthesized from molten bismuth and sulfur. Greenwood, pp. 559–561. Halides In oxidation state +3, bismuth forms salts with all the halogens: , , , and . All hydrolyze in water except . Bismuth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Topological Insulator
A topological insulator is a material whose interior behaves as an electrical insulator while its surface behaves as an electrical conductor, meaning that electrons can only move along the surface of the material. A topological insulator is an insulator for the same reason a " trivial" (ordinary) insulator is: there exists an energy gap between the valence and conduction bands of the material. But in a topological insulator, these bands are, in an informal sense, "twisted", relative to a trivial insulator. The topological insulator cannot be continuously transformed into a trivial one without untwisting the bands, which closes the band gap and creates a conducting state. Thus, due to the continuity of the underlying field, the border of a topological insulator with a trivial insulator (including vacuum, which is topologically trivial) is forced to support conducting edge states. Since this results from a global property of the topological insulator's band structure, local (s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-state Chemistry
Solid-state chemistry, also sometimes referred as materials chemistry, is the study of the Chemical synthesis, synthesis, structure, and properties of solid phase materials. It therefore has a strong overlap with solid-state physics, mineralogy, crystallography, ceramics, metallurgy, thermodynamics, materials science and electronics with a focus on the synthesis of novel materials and their characterization. A diverse range of synthetic techniques, such as the ceramic method and Chemical vapor deposition, chemical vapour depostion, make solid-state materials. Solids can be classified as crystalline or amorphous on basis of the nature of order present in the arrangement of their constituent particles. Their elemental compositions, microstructures, and physical properties can be characterized through a variety of analytical methods. History Because of its direct relevance to products of commerce, solid state inorganic chemistry has been strongly driven by technology. Progress in the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aromaticity
In organic chemistry, aromaticity is a chemical property describing the way in which a conjugated ring of unsaturated bonds, lone pairs, or empty orbitals exhibits a stabilization stronger than would be expected from conjugation alone. The earliest use of the term was in an article by August Wilhelm Hofmann in 1855. There is no general relationship between aromaticity as a chemical property and the olfactory properties of such compounds. Aromaticity can also be considered a manifestation of cyclic delocalization and of resonance. This is usually considered to be because electrons are free to cycle around circular arrangements of atoms that are alternately single- and double- bonded to one another. This commonly seen model of aromatic rings, namely the idea that benzene was formed from a six-membered carbon ring with alternating single and double bonds (cyclohexatriene), was developed by Kekulé (see History section below). Each bond may be seen as a hybrid of a single bo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Orbital Overlap In Aromatic Systems
Orbital may refer to: Sciences Chemistry and physics * Atomic orbital * Molecular orbital * Hybrid orbital Astronomy and space flight * Orbit ** Earth orbit Medicine and physiology * Orbit (anatomy), also known as the ''orbital bone'' * Orbitofrontal cortex, a part of the brain used for decision making Business * Orbital Corporation, an Australian engine technology company * Orbital Sciences Corporation, a U.S. satellite launch and defense systems corporation * Orbital ATK, American aerospace manufacturer formed from the merger of Orbital Sciences Corporation and parts of Alliant Techsystems Transportation * Ring road (or ''orbital road'' in some regions) * Orbital (metro), a rapid transit line usually encircling a city centre * Orbital engine Other uses * ''Orbital'' (novel), a 2023 novel by Samantha Harvey * Orbital (The Culture), artificial worlds from Iain M. Banks's series of science fiction novels, the Culture * Orbital (band), an English electronic dance music duo, who ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Angle-resolved Photoemission Spectroscopy
Angle-resolved photoemission spectroscopy (ARPES) is an experimental technique used in condensed matter physics to probe the allowed energies and momenta of the electrons in a material, usually a crystalline solid. It is based on the photoelectric effect, in which an incoming photon of sufficient energy ejects an electron from the surface of a material. By directly measuring the kinetic energy and emission angle distributions of the emitted photoelectrons, the technique can map the electronic band structure and Fermi surfaces. ARPES is best suited for the study of one- or two-dimensional materials. It has been used by physicists to investigate high-temperature superconductors, graphene, topological materials, quantum well states, and materials exhibiting charge density waves. ARPES systems consist of a monochromatic light source to deliver a narrow beam of photons, a sample holder connected to a manipulator used to position the sample of a material, and an electron spe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gerade Und Ungerade
In physics, a parity transformation (also called parity inversion) is the flip in the sign of ''one'' spatial coordinate. In three dimensions, it can also refer to the simultaneous flip in the sign of all three spatial coordinates (a point reflection): \mathbf: \beginx\\y\\z\end \mapsto \begin-x\\-y\\-z\end. It can also be thought of as a test for chirality of a physical phenomenon, in that a parity inversion transforms a phenomenon into its mirror image. All fundamental interactions of elementary particles, with the exception of the weak interaction, are symmetric under parity transformation. As established by the Wu experiment conducted at the US National Bureau of Standards by Chinese-American scientist Chien-Shiung Wu, the weak interaction is chiral and thus provides a means for probing chirality in physics. In her experiment, Wu took advantage of the controlling role of weak interactions in radioactive decay of atomic isotopes to establish the chirality of the weak force. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Parity (physics)
In physics, a parity transformation (also called parity inversion) is the flip in the sign of ''one'' spatial coordinate. In three dimensions, it can also refer to the simultaneous flip in the sign of all three spatial coordinates (a point reflection): \mathbf: \beginx\\y\\z\end \mapsto \begin-x\\-y\\-z\end. It can also be thought of as a test for chirality of a physical phenomenon, in that a parity inversion transforms a phenomenon into its mirror image. All fundamental interactions of elementary particles, with the exception of the weak interaction, are symmetric under parity transformation. As established by the Wu experiment conducted at the US National Bureau of Standards by Chinese-American scientist Chien-Shiung Wu, the weak interaction is chiral and thus provides a means for probing chirality in physics. In her experiment, Wu took advantage of the controlling role of weak interactions in radioactive decay of atomic isotopes to establish the chirality of the weak f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Density Of States
In condensed matter physics, the density of states (DOS) of a system describes the number of allowed modes or quantum state, states per unit energy range. The density of states is defined as where N(E)\delta E is the number of states in the system of volume V whose energies lie in the range from E to E+\delta E. It is mathematically represented as a distribution by a probability density function, and it is generally an average over the space and time domains of the various states occupied by the system. The density of states is directly related to the dispersion relations of the properties of the system. High DOS at a specific energy level means that many states are available for occupation. Generally, the density of states of matter is continuous. In isolated systems however, such as atoms or molecules in the gas phase, the density distribution is Discrete distribution, discrete, like a spectral density. Local variations, most often due to distortions of the original system, are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
